Patent GB-576214-A (GB)
Title: Improvements in or relating to the mounting of searchlights on aircraft
IPC: B64D47/04
Filed: 1941-09-01
Abstract: 576,214. Searchlights for use on aircraft. HELMORE, W. Sept. 1, 1941, No. 11173. [Classes 75 (ii), 75 (iii) and 75 (iv)] [Also in Group XXI] The effect of beam halation in obscuring the target from an observer on the aircraft is reduced by providing a flattened beam having a greater spread on both sides transversely than in both directions at right angles to the transverse spread, the search light being mounted to permit of traversing the beam in the direction of greatest spread. Further, a radio detector on the aircraft indicates the bearing and range of the target whereby the aircraft can be steered towards the target which is picked up by traversing the searchlight as stated. The beam may also be tilted about a transverse axis to the correct angle for automatic, or other release of a bomb when the target is illuminated. Fig. 2 shows a searchlight 17 mounted in gimbal frames 7, 18 in a casing 15 adapted to be extended or retracted with respect to the fuselage by a piston and cylinder power device 16 as described in Specification 574,970. Figs. 3 and 4 show a similarly mounted searchlight in the nose of an aircraft. The searchlight is provided with a para-elliptic reflector, Fig. 3, the elliptic portions x being at the sides and the parabolic portions y at the top and bottom. The beam emerges through an elongated opening 39, and, whilst the vertical dimension of the beam remains unchanged, the transverse dimension diverges thus providing beyond the aircraft a flattened beam as previously defined. In the constructions shown in Fig. 2 and Figs. 3 and 4, the searchlight is moved in elevation by motor 22 and control device 24 and in traverse by motor 20 and driftcontrol apparatus 21. The bomb-sighting mechanism 32 controlled by altimeter 33 and speed-indicator 34 serves to set by motor 40 an arm 30 in elevation to suit the correct angle of release. Depressional movement of the searchlight to the release angle causes a rod 31 on the frame 18 to contact the arm 30 to complete the electric circuit to release gears 25, 26, 27, for dropping a bomb, a marker buoy or a flare respectively. If desired, the time for release may be indicated and release effected by hand through control 36. The target is picked up and illuminated with the aid of a radio detector 6, .Fig. 4, as described in Specification 574,970. In a modification, Fig. 6, a fixed searchlight is mounted in the nose of the aircraft for projection of the beam through an elongated aperture in a flat glass 47 fitted with an annular gapped ring 48 of known kind to minimize air disturbance. The beam is rotated about a longitudinal axis by means 45. In a further modification, the adjustable searchlight is mounted beneath the wing of the aircraft the beam being rotatable by means 45 about its longitudinal axis. When allowance for drift is made by bringing the target to a position across the beam, a portion of the beam may be identified by providing an auxiliary parabolic reflector 38 universally mounted so that a more intense beam may be moved relatively to the main. beam. Specifications 575,093 and 576,118,. [Group XL], also are referred to.